Insulator sleeve



Dec. 10, 1963 INSULATOR SLEEVE Filed Dec. 20, 1961 e. H. A. LAINE 3,113,998

3,113,998 INSULATGR SLEEVE v Giista H. A. Laine, Kalliolinnantie 1336,

Helsinki, Finland Filed Dec. 20, 1961, Ser. No. 160,839 Claims priority, application Finland Dec. 20, 1960 4 Claims. (Cl. 174138) The present invention relates to an insulator sleeve for fixing a line insulator such as a porcelain or glass insulator on an insulator hook or pin, saidinsulator sleeve being formed of a sleeve made of elastic material such as plastic and closed at one of its ends.

Known insulator sleeves made of wood, cardboard, or plastic have certain disadvantages. Each insulator size and each insulator hook or insulator pin size requires insulator sleeves of corresponding size. Even so, it is not possible safely to attach the insulator to the hook or pin by means of known sleeves owing to the fiact that the diameter of the cylindrical hole in the insulator and the diameter of the insulator hook or pin may vary. A tolerance of is customary.

When a hook or pin is screwed into an insulator the threads of the insulator hole as well as the threads of the pin cut corresponding threads into the inner and the outer Wall of a sleeve made of plastic. This reduces the strengthof the sleeve and weakens the anchoring of the insulator. The threads may even cut through the wall of the sleeve. Plastic sleeves [also age very fast owing to electric leakage discharge passing through the insulator and the sleeve to the pin.

It is an object of the present invention to eliminate the disadvantages of the known devices, and to provide a sleeve the size of which is automatically adjusted within comparatively large limits to the diameters oi the, insulator hook or pin and of the cavity in the insulator.

A preferred embodiment of the invention will be described in detail in the following passages of the specification with reference to the accompanying drawing in which 7 FIG. 1 is a side view of the sleeve, FIG. 2 is a top plan view of the sleeve of FIG. 1,

FIG. 3 is a developed view of the side wall of the sleeve of FIG. 1,

FIG. 4 is a side view of the sleeve of FIG. 1 in the enlarged condition, and I FIG. 5 is a top plan view of the sleeve of FIG. 4.

The sleeve 1 has the general shape of a cylindrical tube having an annular side wall 3 and a radial end wall or top wall 4 which enclose an axial recess in the sleeve. sleeve is made of elastic material such as plastic and is provided with two kinds of axial slits uniformly spaced about the sleeve axis. The slits 2 start at some distance from the lower edge of the axial side wall 3. They extend across the top wall 4 of the sleeve and communicate with each other. The slits 5 are positioned between the slits 2. They extend from the lower edge of the side Wall 3 and terminate near the upper edge thereof.

The sleeve 1 has three slits 2 spaced 120 from each other, and three slits 5 positioned between the slits 2 and also spaced 120 from each other.

When a sleeve normally dimensioned for acertain standard size is used for the next larger standard size, the sleeve expands uniformly in all directions as seen in FIGS. 4 and 5. It is therefore self-adjusting and provides a very firm anchoring for the insulator.

The sleeve according to the invention consists essentially of narrow [axial strips circumferentially connected with each other. The narrow resilient strips conform to The United States Patent 0 3,113,998 I Patented Dec. 10,. 1963 out having threads \cut into the wall thereof as in known insulator sleeves. Thus, the original thickness of the wall of the sleeve is not reduced, and very firm anchoring of the insulator is achieved.

The electric leakage discharge may pass directly through the slits inthe top of the sleeve to the hook, and does not harmfully aiiect the material of the sleeve.

While a preferred embodiment of. the invention has been described m any modifications may be made without departingirom the scope of the invention. Thus, the slits 5 may be eliminated. Furthermore, the number or" slits may be varied e.g. two opposed slits 2 and two slits 5 positioned ltherebetween. It is essential that the slits be arranged so that the sleeve is divided into connected axially elongated strips and is thereby self-adjusting as to 7 its size. Such a sleeve can adapt itself to variations in the diameter of the insulator cavity and/ or insulator hook or pin and can conform to their threads so that firm anchoring of an insulator is achieved.

What I claim is:

l. insulating sleeve for use between an insulator and a supporting pin, said sleeve having an axis and comprising (a) a side wall substantially annular about said axis and defining a recess for receiving said pin; and

(b) an end wall transverse of said axis and substantially closing an axial end of said recess,

. '(1) said walls being formed with a plurality of first slits spaced about said axis, a portion of each slit extending axially in said side wall over a major portion of the axial length of said side wall, and, another portion of each slit extending in said end wall,

(2) the respective portions of said slits in said end wall communicating with each other, and

(3) said side wall being formed with a plurality of second slits spaced about said axis, each second slit being circumierentially interposed between two adjacent first slits and extending from an edge portion of said side wall remote from said end wall over a major portion of the axial length of said side wall toward the edge portion of said side wall adjacent said end wall. 2. A sleeve as set forth in claim 1, wherein said sleeve is of resilient plastic. 3. A sleeve as set forth in claim 1, whereinsaid first and second slits are substantially uniformly spaced about said axis.,

4. A sleeve as set forth in claim 1, wherein said portions of said first slits in said side wall are circumferentially spaced from each other substantially degrees, and said second slits are cincumierentially spaced from each other substantially 120 degrees.

References Cited in the file of this patent UNITED STATES PATENTS 

1. AN INSULATING SLEEVE FOR USE BETWEEN AN INSULATOR AND A SUPPORTING PIN, SAID SLEEVE HAVING AN AXIS AND COMPRISING (A) A SIDE WALL SUBSTANTIALLY ANNULAR ABOUT SAID AXIS AND DEFINING A RECESS FOR RECEIVING SAID PIN; AND (B) AN END WALL TRANSVERSE OF SAID AXIS AND SUBSTANTIALLY CLOSING AN AXIAL END OF SAID RECESS, (1) SAID WALLS BEING FORMED WITH A PLURALITY OF FIRST SLITS SPACED ABOUT SAID AXIS, A PORTION OF EACH SLIT EXTENDING AXIALLY IN SAID SIDE WALL OVER A MAJOR PORTION OF THE AXIAL LENGTH OF SAID SIDE WALL, AND ANOTHER PORTION OF EACH SLIT EXTENDING IN SAID END WALL, 